/Engine/Plugins/Experimental/PlanarCutPlugin/Source/PlanarCut/Public/PlanarCut.h
Cut multiple Geometry groups inside a GeometryCollection with Planes, and add each cut cell back to the GeometryCollection as a new child of their source Geometry. For geometries that would not be cut, nothing is added.
index of first new geometry in the Output GeometryCollection, or -1 if no geometry was added
int32 CutMultipleWithMultiplePlanes ( const [TArrayView](API\Runtime\Core\Containers\TArrayView)< const FPlane > & Planes, [FInternalSurfaceMaterials](API\Plugins\PlanarCut\FInternalSurfaceMaterials) & InternalSurfaceMaterials, [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) & Collection, const [TArrayView](API\Runtime\Core\Containers\TArrayView)< const int32 > & TransformIndices, double Grout, double CollisionSampleSpacing, int32 RandomSeed, const [TOptional](API\Runtime\Core\IO\TOptional)< FTransform > & TransformCollection, bool bSetDefaultInternalMaterialsFromCollection, [FProgressCancel](API\Runtime\GeometryCore\Util\FProgressCancel) * Progress )